That's exactly it. I ran an H100 with very good 120x38s on my x5690 and it had a hard time after about 4300 1.375v. Todays quad cores sip power compared to that old beast, so they more than likely wont get heatsoaked as quick.. unless their caseflow is not flowing as well as they think. I think people are in love with the clean looks, and the "water cooled" feel. I know I was. My 3770k doesn't get my LGMRT warm in the slightest with the fan running, but my x5690 can. A different kind of heat.. beast heat
I prefer my heatsinks these days, no muss, no fuss, no worrys, and I can still keep my overclock in the summer (for now). Win/win.
Its not as clean as an AIO, or CLC or whatever they are.. but if you buy a nice one, a good one, like in the top 5, then its like art, if you have an appreciation for modern manufacturing techniques done proplerly.
I'm kind of all over the place in this post. Cannabis is legal here now, and I've got some good stuff